Shell group eyes development of deepwater discovery in gulf

A group led by a unit of Shell Oil Co. expects next year to decide on a plan to develop another large, ultradeepwater, oil and gas field in the Gulf of Mexico. A team that includes Shell Exploration & Production Co., BP Exploration Inc. (BPX), Conoco Inc., and Exxon Co. U.S.A. is evaluating development options for Ursa field. Ursa lies under a six tract unit in 3,950 ft of water in the Mississippi Canyon(17850 bytes) federal planning area about 135 miles southeast of New Orleans.

Aug. 14, 1995

4 min read

A group led by a unit of Shell Oil Co. expects next year to decide on a plan to develop another large, ultradeepwater, oil and gas field in the Gulf of Mexico.

A team that includes Shell Exploration & Production Co., BP Exploration Inc. (BPX), Conoco Inc., and Exxon Co. U.S.A. is evaluating development options for Ursa field. Ursa lies under a six tract unit in 3,950 ft of water in the Mississippi Canyon(17850 bytes) federal planning area about 135 miles southeast of New Orleans.

Shell Offshore Inc. (SOI) and BP completed Ursa's discovery well in 1991 on Mississippi Canyon Block 854. SOI and BP drilled the wildcat with Sonat's Discoverer Seven Seas drillship.

Based on that well and two delineation wells and a sidetrack, Ursa partners estimate size of the field between two other high profile Shell operated deepwater developments in the gulf, Mars and Auger fields.

Mars partners Shell and BP plan to produce Mars oil and gas with a tension leg platform in 2,933 ft of water on Mississippi Canyon Block 807, just east of Ursa (OGJ, Oct. 11, 1993, p. 28). Production is to begin in fourth quarter 1996, with first phase recovery expected to reach 500 million bbl of oil equivalent. Second phase operations could boost total recovery to more than 700 million BOE.

Shell expects Auger gross recovery to exceed 220 million BOE. Auger production started in April 1994 (OGJ Apr. 25, 1994, p. 30). The field produces through a TLP installed in late 1993 in 2,860 ft of water on Garden Banks Block 426.

Partly because of its interest in Ursa, BPX early this month disclosed it has boosted its estimated reserves in the gulf to 600-700 million BOE from 300 million BOE. However, Ursa partners will delay a final development commitment on the field to await results of an appraisal well to be spudded late this year.

The Ursa unit covers Mississippi Canyon Blocks 808, 809, 810, 852, 853, and 854. Ursa operator Shell holds 45% interest in the unit, BPX 23%, and Conoco and Exxon 16% each.

Deepwater developments

A decision to develop Ursa would entrench Shell and BPX as the Gulf of Mexico's dominant deepwater oil and gas producers.

SOI owns nearly one-third of all acreage leased in the gulf in more than 1,500 ft of water. BPX holds interests in 389 gulf tracts in water more than 600 ft deep.

Start-up of Ursa production after 1996 would bring to eight the number of Shell operated development projects in the Gulf of Mexico in more than 1,500 ft of water. In addition to Auger, Mars, and Ursa, the list would include:

Tahoe field in 1,500 ft of water on Viosca Knoll Block 783, which went on production early in 1994.
Popeye field, 2,100 ft of water, Green Canyon Block 116, to begin production this fall (OGJ, Apr. 10, p. 26).
Rocky field, 1,755 ft of water, Green Canyon Block 110, also to begin producing later this year.
Ram-Powell field, 3,200 ft of water, Viosca Knoll Block 956, to begin production in 1997 (OGJ, Jan. 30, p. 41).
Mensa field, 5,400 ft of water, Mississippi Canyon Block 687, to start production in 1997 (OGJ, June 5, p. 30).

In addition to boosting its reserves in the gulf, BPX expects deepwater developments to hike its gulf-wide oil and gas flow by the end of the decade to about 120,000 BOE/d from 35,000 BOE/d at present. BPX plans to drill four company operated wildcats in the gulf in the next few years, all in more than 600 ft of water.

Much of BPX's incremental oil and gas production in the gulf in coming years will come from Ursa and Wasatch fields.

Wasatch is a Marathon Oil Co. operated prospect in 2,670 ft of water on Green Canyon Blocks 200 and 244 in which BPX and SOI each hold a 33% interest (OGJ, July 31, p. 42).

BPX holds a 29% interest in Mars and 12.5% in Popeye. The company also has 75% interest in and operates the gulf's Pompano field, where it produces oil and gas from a fixed platform in 1,290 ft of water on Viosca Knoll Block 989 (OGJ, Sept. 5, 1994, p. 34).

Other BPX operated fields in the Gulf of Mexico and the company's shares of interest are Snapper 100%; Mobile Block 821, 100%; West Cameron Block 143, 100%; Amberjack 66, 3%; and Ewing Bank Block 826, 40%.